Age 16 to 18 Short Challenge Level:
In this problem there are three equations of straight lines and
three more complicated relations between x and y.
Consider all the factors of the non-linear expressions to discover
what points lie on their graphs.
The more complicated relations have extra points (x, y) which
satisfy the relations but the computer does not notice.You have to
be cleverer than the computer and find the extra points satisfying
the relation that do not show up on the computer's graph. To do
this you need to look at all the factors in the expressions and
find when they are zero.